Acquisitions (Details) € in Millions			3 Months Ended
	Mar. 31, 2019 USD ($)	Apr. 26, 2017 EUR (€)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Total cash consideration for acquisitions, net of cash acquired			$ 600,000	$ 41,000,000
Payment for contingent consideration liability, financing activities			600,000	8,700,000
Initial acquisition payments			0	8,200,000
Payments of contingent consideration for acquisitions			600,000	$ 32,800,000
7S Group GmbH
Business Acquisition [Line Items]
Loss contingency, additional consideration sought from the seller of 7S	$ 23,300,000	€ 20.8
Estimate of possible loss	$ 0		$ 0